Open Access. Powered by Scholars. Published by Universities.®

Life Sciences Commons™

Open Access. Powered by Scholars. Published by Universities.®

Biochemistry, Biophysics, and Structural Biology

University of Kentucky

2016

Articles 1 - 30 of 55

Full-Text Articles in Life Sciences

Rit1 Gtpase Regulates Sox2 Transcriptional Activity And Hippocampal Neurogenesis, Sajad Mir, Weikang Cai, Douglas A. Andres Dec 2016

Rit1 Gtpase Regulates Sox2 Transcriptional Activity And Hippocampal Neurogenesis, Sajad Mir, Weikang Cai, Douglas A. Andres

Molecular and Cellular Biochemistry Faculty Publications

Adult neurogenesis, the process of generating mature neurons from neuronal progenitor cells, makes critical contributions to neural circuitry and brain function in both healthy and disease states. Neurogenesis is a highly regulated process in which diverse environmental and physiological stimuli are relayed to resident neural stem cell populations to control the transcription of genes involved in self-renewal and differentiation. Understanding the molecular mechanisms governing neurogenesis is necessary for the development of translational strategies to harness this process for neuronal repair. Here we report that the Ras-related GTPase RIT1 serves to control the sequential proliferation and differentiation of adult hippocampal neural …

Go to article

Respective Contributions Of Single And Compound Granule Fusion To Secretion By Activated Platelets, Anita Eckly, Jean-Yves Rinckel, Fabienne Proamer, Neslihan Ulas, Smita Joshi, Sidney W. Whiteheart, Christian Gachet Nov 2016

Respective Contributions Of Single And Compound Granule Fusion To Secretion By Activated Platelets, Anita Eckly, Jean-Yves Rinckel, Fabienne Proamer, Neslihan Ulas, Smita Joshi, Sidney W. Whiteheart, Christian Gachet

Molecular and Cellular Biochemistry Faculty Publications

Although granule secretion is pivotal in many platelet responses, the fusion routes of α and δ granule release remain uncertain. We used a 3D reconstruction approach based on electron microscopy to visualize the spatial organization of granules in unstimulated and activated platelets. Two modes of exocytosis were identified: a single mode that leads to release of the contents of individual granules and a compound mode that leads to the formation of granule-to-granule fusion, resulting in the formation of large multigranular compartments. Both modes occur during the course of platelet secretion. Single fusion events are more visible at lower levels of …

Go to article

The Nuts And Bolts Of The Platelet Release Reaction, Smita Joshi, Sidney W. Whiteheart Nov 2016

The Nuts And Bolts Of The Platelet Release Reaction, Smita Joshi, Sidney W. Whiteheart

Molecular and Cellular Biochemistry Faculty Publications

Secretion is essential to many of the roles that platelets play in the vasculature, e.g., thrombosis, angiogenesis, and inflammation, enabling platelets to modulate the microenvironment at sites of vascular lesions with a myriad of bioactive molecules stored in their granules. Past studies demonstrate that granule cargo release is mediated by Soluble NSF Attachment Protein Receptor (SNARE) proteins, which are required for granule-plasma membrane fusion. Several SNARE regulators, which control when, where, and how the SNAREs interact, have been identified in platelets. Additionally, platelet SNAREs are controlled by post-translational modifications, e.g., phosphorylation and acylation. Although there have been many …

Go to article

P70s6k1 (S6k1)-Mediated Phosphorylation Regulates Phosphatidylinositol 4-Phosphate 5-Kinase Type I Γ Degradation And Cell Invasion, Naser Jafari, Qiaodan Zheng, Liqing Li, Wei Li, Lei Qi, Jianyong Xiao, Tianyan Gao, Cai Huang Oct 2016

P70s6k1 (S6k1)-Mediated Phosphorylation Regulates Phosphatidylinositol 4-Phosphate 5-Kinase Type I Γ Degradation And Cell Invasion, Naser Jafari, Qiaodan Zheng, Liqing Li, Wei Li, Lei Qi, Jianyong Xiao, Tianyan Gao, Cai Huang

Markey Cancer Center Faculty Publications

Phosphatidylinositol 4-phosphate 5-kinase type I γ (PIPKIγ90) ubiquitination and subsequent degradation regulate focal adhesion assembly, cell migration, and invasion. However, it is unknown how upstream signals control PIPKIγ90 ubiquitination or degradation. Here we show that p70S6K1 (S6K1), a downstream target of mechanistic target of rapamycin (mTOR), phosphorylates PIPKIγ90 at Thr-553 and Ser-555 and that S6K1-mediated PIPKIγ90 phosphorylation is essential for cell migration and invasion. Moreover, PIPKIγ90 phosphorylation is required for the development of focal adhesions and invadopodia, key machineries for cell migration and invasion. Surprisingly, substitution of Thr-553 and Ser-555 …

Go to article

Pleckstrin Homology (Ph) Domain Leucine-Rich Repeat Protein Phosphatase Controls Cell Polarity By Negatively Regulating The Activity Of Atypical Protein Kinase C, Xiaopeng Xiong, Xin Li, Yang-An Wen, Tianyan Gao Oct 2016

Pleckstrin Homology (Ph) Domain Leucine-Rich Repeat Protein Phosphatase Controls Cell Polarity By Negatively Regulating The Activity Of Atypical Protein Kinase C, Xiaopeng Xiong, Xin Li, Yang-An Wen, Tianyan Gao

Markey Cancer Center Faculty Publications

The proper establishment of epithelial polarity allows cells to sense and respond to signals that arise from the microenvironment in a spatiotemporally controlled manner. Atypical PKCs (aPKCs) are implicated as key regulators of epithelial polarity. However, the molecular mechanism underlying the negative regulation of aPKCs remains largely unknown. In this study, we demonstrated that PH domain leucine-rich repeat protein phosphatase (PHLPP), a novel family of Ser/Thr protein phosphatases, plays an important role in regulating epithelial polarity by controlling the phosphorylation of both aPKC isoforms. Altered expression of PHLPP1 or PHLPP2 disrupted polarization of Caco2 cells grown in 3D cell cultures …

Go to article

Mycosins Are Required For The Stabilization Of The Esx-1 And Esx-5 Type Vii Secretion Membrane Complexes, Vincent J. C. Van Winden, Roy Ummels, Sander R. Piersma, Connie R. Jiménez, Konstantin V. Korotkov, Wilbert Bitter, Edith N. G. Houben Oct 2016

Mycosins Are Required For The Stabilization Of The Esx-1 And Esx-5 Type Vii Secretion Membrane Complexes, Vincent J. C. Van Winden, Roy Ummels, Sander R. Piersma, Connie R. Jiménez, Konstantin V. Korotkov, Wilbert Bitter, Edith N. G. Houben

Molecular and Cellular Biochemistry Faculty Publications

ABSTRACT Pathogenic mycobacteria contain up to five type VII secretion (T7S) systems, ESX-1 to ESX-5. One of the conserved T7S components is the serine protease mycosin (MycP). Strikingly, whereas MycP is essential for secretion, the protease activity of MycP1 in Mycobacterium tuberculosis has been shown to be dispensable for secretion. The essential role of MycP therefore remains unclear. Here we show that MycP1 and MycP5 of M. marinum have similar phenotypes, confirming that MycP has a second unknown function that is essential for its T7S system. To investigate whether this role is related to proper functioning of …

Go to article

Spyb, A Small Heme-Binding Protein, Affects The Composition Of The Cell Wall In Streptococcus Pyogenes, Rebecca J. Edgar, Jing Chen, Sashi Kant, Elena Rechkina, Jeffrey S. Rush, Lennart S. Forsberg, Bernhard Jaehrig, Parastoo Azadi, Veronika Tchesnokova, Evgeni V. Sokurenko, Haining Zhu, Konstantin V. Korotkov, Vijay Pancholi, Natalia Korotkova Oct 2016

Spyb, A Small Heme-Binding Protein, Affects The Composition Of The Cell Wall In Streptococcus Pyogenes, Rebecca J. Edgar, Jing Chen, Sashi Kant, Elena Rechkina, Jeffrey S. Rush, Lennart S. Forsberg, Bernhard Jaehrig, Parastoo Azadi, Veronika Tchesnokova, Evgeni V. Sokurenko, Haining Zhu, Konstantin V. Korotkov, Vijay Pancholi, Natalia Korotkova

Molecular and Cellular Biochemistry Faculty Publications

Streptococcus pyogenes (Group A Streptococcus or GAS) is a hemolytic human pathogen associated with a wide variety of infections ranging from minor skin and throat infections to life-threatening invasive diseases. The cell wall of GAS consists of peptidoglycan sacculus decorated with a carbohydrate comprising a polyrhamnose backbone with immunodominant N-acetylglucosamine side-chains. All GAS genomes contain the spyBA operon, which encodes a 35-amino-acid membrane protein SpyB, and a membrane-bound C3-like ADP-ribosyltransferase SpyA. In this study, we addressed the function of SpyB in GAS. Phenotypic analysis of a spyB deletion mutant revealed increased bacterial aggregation, and reduced sensitivity to β-lactams of the …

Go to article

Inhibition Of Human Metapneumovirus Binding To Heparan Sulfate Blocks Infection In Human Lung Cells And Airway Tissues, Edita M. Klimyte, Stacy E. Smith, Pasqua Oreste, David Lembo, Rebecca Ellis Dutch Oct 2016

Inhibition Of Human Metapneumovirus Binding To Heparan Sulfate Blocks Infection In Human Lung Cells And Airway Tissues, Edita M. Klimyte, Stacy E. Smith, Pasqua Oreste, David Lembo, Rebecca Ellis Dutch

Molecular and Cellular Biochemistry Faculty Publications

Human metapneumovirus (HMPV), a recently discovered paramyxovirus, infects nearly 100% of the world population and causes severe respiratory disease in infants, the elderly, and immunocompromised patients. We previously showed that HMPV binds heparan sulfate proteoglycans (HSPGs) and that HMPV binding requires only the viral fusion (F) protein. To characterize the features of this interaction critical for HMPV binding and the role of this interaction in infection in relevant models, we utilized sulfated polysaccharides, heparan sulfate mimetics, and occluding compounds. Iota-carrageenan demonstrated potent anti-HMPV activity by inhibiting binding to lung cells mediated by the F protein. Furthermore, analysis of a minilibrary …

Go to article

An Arginine Finger Regulates The Sequential Action Of Asymmetrical Hexameric Atpase In The Double-Stranded Dna Translocation Motor, Zhengyi Zhao, Gian Marco De-Donatis, Chad T. Schwartz, Huaming Fang, Jingyuan Li, Peixuan Guo Oct 2016

An Arginine Finger Regulates The Sequential Action Of Asymmetrical Hexameric Atpase In The Double-Stranded Dna Translocation Motor, Zhengyi Zhao, Gian Marco De-Donatis, Chad T. Schwartz, Huaming Fang, Jingyuan Li, Peixuan Guo

Pharmaceutical Sciences Faculty Publications

Biological motors are ubiquitous in living systems. Currently, how the motor components coordinate the unidirectional motion is elusive in most cases. Here, we report that the sequential action of the ATPase ring in the DNA packaging motor of bacteriophage ϕ29 is regulated by an arginine finger that extends from one ATPase subunit to the adjacent unit to promote noncovalent dimer formation. Mutation of the arginine finger resulted in the interruption of ATPase oligomerization, ATP binding/hydrolysis, and DNA translocation. Dimer formation reappeared when arginine mutants were mixed with other ATPase subunits that can offer the arginine to promote their interaction. Ultracentrifugation …

Go to article

Human Metapneumovirus Induces Reorganization Of The Actin Cytoskeleton For Direct Cell-To-Cell Spread, Farah El Najjar, Nicolás Cifuentes-Muñoz, Jing Chen, Haining Zhu, Ursula J. Buchholz, Carole L. Moncman, Rebecca Ellis Dutch Sep 2016

Human Metapneumovirus Induces Reorganization Of The Actin Cytoskeleton For Direct Cell-To-Cell Spread, Farah El Najjar, Nicolás Cifuentes-Muñoz, Jing Chen, Haining Zhu, Ursula J. Buchholz, Carole L. Moncman, Rebecca Ellis Dutch

Molecular and Cellular Biochemistry Faculty Publications

Paramyxovirus spread generally involves assembly of individual viral particles which then infect target cells. We show that infection of human bronchial airway cells with human metapneumovirus (HMPV), a recently identified paramyxovirus which causes significant respiratory disease, results in formation of intercellular extensions and extensive networks of branched cell-associated filaments. Formation of these structures is dependent on actin, but not microtubule, polymerization. Interestingly, using a co-culture assay we show that conditions which block regular infection by HMPV particles, including addition of neutralizing antibodies or removal of cell surface heparan sulfate, did not prevent viral spread from infected to new target cells. …

Go to article

Comparative Analysis Of Linker Histone H1, Mecp2, And Hmgd1 On Nucleosome Stability And Target Site Accessibility, Caitlyn Riedmann, Yvonne N. Fondufe-Mittendorf Sep 2016

Comparative Analysis Of Linker Histone H1, Mecp2, And Hmgd1 On Nucleosome Stability And Target Site Accessibility, Caitlyn Riedmann, Yvonne N. Fondufe-Mittendorf

Molecular and Cellular Biochemistry Faculty Publications

Chromatin architectural proteins (CAPs) bind the entry/exit DNA of nucleosomes and linker DNA to form higher order chromatin structures with distinct transcriptional outcomes. How CAPs mediate nucleosome dynamics is not well understood. We hypothesize that CAPs regulate DNA target site accessibility through alteration of the rate of spontaneous dissociation of DNA from nucleosomes. We investigated the effects of histone H1, high mobility group D1 (HMGD1), and methyl CpG binding protein 2 (MeCP2), on the biophysical properties of nucleosomes and chromatin. We show that MeCP2, like the repressive histone H1, traps the nucleosome in a more compact mononucleosome structure. Furthermore, histone …

Go to article

Lipophosphoglycans From Leishmania Amazonensis Strains Display Immunomodulatory Properties Via Tlr4 And Do Not Affect Sand Fly Infection, Paula M. Nogueira, Rafael R. Assis, Ana C. Torrecilhas, Elvira M. Saraiva, Natália L. Pessoa, Marco A. Campos, Eric F. Marialva, Cláudia M. Ríos-Velasquez, Felipe A. Pessoa, Nágila F. Secundino, Jerônimo N. Rugani, Elsa Nieves, Salvatore J. Turco, Maria N. Melo, Rodrigo P. Soares Aug 2016

Lipophosphoglycans From Leishmania Amazonensis Strains Display Immunomodulatory Properties Via Tlr4 And Do Not Affect Sand Fly Infection, Paula M. Nogueira, Rafael R. Assis, Ana C. Torrecilhas, Elvira M. Saraiva, Natália L. Pessoa, Marco A. Campos, Eric F. Marialva, Cláudia M. Ríos-Velasquez, Felipe A. Pessoa, Nágila F. Secundino, Jerônimo N. Rugani, Elsa Nieves, Salvatore J. Turco, Maria N. Melo, Rodrigo P. Soares

Molecular and Cellular Biochemistry Faculty Publications

The immunomodulatory properties of lipophosphoglycans (LPG) from New World species of Leishmania have been assessed in Leishmania infantum and Leishmania braziliensis, the causative agents of visceral and cutaneous leishmaniasis, respectively. This glycoconjugate is highly polymorphic among species with variation in sugars that branch off the conserved Gal(β1,4)Man(α1)-PO4 backbone of repeat units. Here, the immunomodulatory activity of LPGs from Leishmania amazonensis, the causative agent of diffuse cutaneous leishmaniasis, was evaluated in two strains from Brazil. One strain (PH8) was originally isolated from the sand fly and the other (Josefa) was isolated from a human case. The ability of …

Go to article

Als Mutant Sod1 Interacts With G3bp1 And Affects Stress Granule Dynamics, Jozsef Gal, Lisha Kuang, Kelly R. Barnett, Brian Z. Zhu, Susannah C. Shissler, Konstantin V. Korotkov, Lawrence J. Hayward, Edward J. Kasarskis, Haining Zhu Aug 2016

Als Mutant Sod1 Interacts With G3bp1 And Affects Stress Granule Dynamics, Jozsef Gal, Lisha Kuang, Kelly R. Barnett, Brian Z. Zhu, Susannah C. Shissler, Konstantin V. Korotkov, Lawrence J. Hayward, Edward J. Kasarskis, Haining Zhu

Molecular and Cellular Biochemistry Faculty Publications

Amyotrophic lateral sclerosis (ALS) is a fatal neurodegenerative disease. Mutations in Cu/Zn superoxide dismutase (SOD1) are responsible for approximately 20 % of the familial ALS cases. ALS-causing SOD1 mutants display a gain-of-toxicity phenotype, but the nature of this toxicity is still not fully understood. The Ras GTPase-activating protein-binding protein G3BP1 plays a critical role in stress granule dynamics. Alterations in the dynamics of stress granules have been reported in several other forms of ALS unrelated to SOD1. To our surprise, the mutant G93A SOD1 transgenic mice exhibited pathological cytoplasmic inclusions that co-localized with G3BP1-positive granules in spinal cord motor neurons. …

Go to article

The Confounding Effects Of Particle Size And Substrate Bulk Density On Phanerochaete Chrysosporium Pretreatment On Panicum Virgatum, Amanda N. Hickman, Sue E. Nokes, William S. Sympson, Mathew J. Ruwaya, Michael D. Montross, Barbara L. Knutson Jul 2016

The Confounding Effects Of Particle Size And Substrate Bulk Density On Phanerochaete Chrysosporium Pretreatment On Panicum Virgatum, Amanda N. Hickman, Sue E. Nokes, William S. Sympson, Mathew J. Ruwaya, Michael D. Montross, Barbara L. Knutson

Biosystems and Agricultural Engineering Faculty Publications

Phanerochaete chrysosporium treatment is less effective as a biological pretreatment on feedstock with larger particle sizes. We hypothesized that the improved effectiveness of the pretreatment when smaller particle sizes are used may be due to the inherently higher bulk density with smaller particle sizes. The effects of substrate bulk density and particle size on the efficacy of P. chrysosporium pretreatment of switchgrass (Panicum virgatum) was tested experimentally. Phanerochaete chrysosporium was grown on senesced switchgrass (2 different particle sizes) with various bulk densities. In all treatments, the fungal-pretreated samples released more glucose during enzymatic saccharification than the control sample. …

Go to article

Ten Simple Rules For Taking Advantage Of Git And Github, Yasset Perez-Riverol, Laurent Gatto, Rui Wang, Timo Sachsenberg, Julian Uszkoreit, Felipe Da Veiga Leprevost, Christian Fufezan, Tobias Ternent, Stephen J. Eglen, Daniel S. Katz, Tom J. Pollard, Alexander Konovalov, Robert M. Flight, Kai Blin, Juan Antonio Vizcaíno Jul 2016

Ten Simple Rules For Taking Advantage Of Git And Github, Yasset Perez-Riverol, Laurent Gatto, Rui Wang, Timo Sachsenberg, Julian Uszkoreit, Felipe Da Veiga Leprevost, Christian Fufezan, Tobias Ternent, Stephen J. Eglen, Daniel S. Katz, Tom J. Pollard, Alexander Konovalov, Robert M. Flight, Kai Blin, Juan Antonio Vizcaíno

Molecular and Cellular Biochemistry Faculty Publications

No abstract provided.

Go to article

Distinct And Shared Functions Of Als-Associated Proteins Tdp-43, Fus And Taf15 Revealed By Multisystem Analyses, Katannya Kapeli, Gabriel A. Pratt, Anthony Q. Vu, Kasey R. Hutt, Fernando J. Martinez, Balaji Sundararaman, Ranjan Batra, Peter Freese, Nicole J. Lambert, Stephanie C. Huelga, Seung J. Chun, Tiffany Y. Liang, Jeremy Chang, John P. Donohue, Lily Shiue, Jiayu Zhang, Haining Zhu, Franca Cambi, Edward J. Kasarskis, Shawn Hoon, Manuel Ares Jr., Christopher B. Burge, John Ravits, Frank Rigo, Gene W. Yeo Jul 2016

Distinct And Shared Functions Of Als-Associated Proteins Tdp-43, Fus And Taf15 Revealed By Multisystem Analyses, Katannya Kapeli, Gabriel A. Pratt, Anthony Q. Vu, Kasey R. Hutt, Fernando J. Martinez, Balaji Sundararaman, Ranjan Batra, Peter Freese, Nicole J. Lambert, Stephanie C. Huelga, Seung J. Chun, Tiffany Y. Liang, Jeremy Chang, John P. Donohue, Lily Shiue, Jiayu Zhang, Haining Zhu, Franca Cambi, Edward J. Kasarskis, Shawn Hoon, Manuel Ares Jr., Christopher B. Burge, John Ravits, Frank Rigo, Gene W. Yeo

Molecular and Cellular Biochemistry Faculty Publications

The RNA-binding protein (RBP) TAF15 is implicated in amyotrophic lateral sclerosis (ALS). To compare TAF15 function to that of two ALS-associated RBPs, FUS and TDP-43, we integrate CLIP-seq and RNA Bind-N-Seq technologies, and show that TAF15 binds to ∼4,900 RNAs enriched for GGUA motifs in adult mouse brains. TAF15 and FUS exhibit similar binding patterns in introns, are enriched in 3′ untranslated regions and alter genes distinct from TDP-43. However, unlike FUS and TDP-43, TAF15 has a minimal role in alternative splicing. In human neural progenitors, TAF15 and FUS affect turnover of their RNA targets. In human stem cell-derived motor …

Go to article

Red-Shifted Aequorin Variants Incorporating Non-Canonical Amino Acids: Applications In In Vivo Imaging, Kristen M. Grinstead, Laura Rowe, Mark Ensor, Smita Joel, Pirouz Daftarian, Emre Dikici, Jean-Marc Zingg, Sylvia Daunert Jul 2016

Red-Shifted Aequorin Variants Incorporating Non-Canonical Amino Acids: Applications In In Vivo Imaging, Kristen M. Grinstead, Laura Rowe, Mark Ensor, Smita Joel, Pirouz Daftarian, Emre Dikici, Jean-Marc Zingg, Sylvia Daunert

Pharmaceutical Sciences Faculty Publications

The increased importance of in vivo diagnostics has posed new demands for imaging technologies. In that regard, there is a need for imaging molecules capable of expanding the applications of current state-of-the-art imaging in vivo diagnostics. To that end, there is a desire for new reporter molecules capable of providing strong signals, are non-toxic, and can be tailored to diagnose or monitor the progression of a number of diseases. Aequorin is a non-toxic photoprotein that can be used as a sensitive marker for bioluminescence in vivo imaging. The sensitivity of aequorin is due to the fact that bioluminescence is a …

Go to article

20-Hydroxyecdysone (20e) Primary Response Gene E75 Isoforms Mediate Steroidogenesis Autoregulation And Regulate Developmental Timing In Bombyx, Kang Li, Ling Tian, Zhongjian Guo, Sanyou Guo, Jianzhen Zhang, Shi-Hong Gu, Subba Reddy Palli, Yang Cao, Sheng Li Jun 2016

20-Hydroxyecdysone (20e) Primary Response Gene E75 Isoforms Mediate Steroidogenesis Autoregulation And Regulate Developmental Timing In Bombyx, Kang Li, Ling Tian, Zhongjian Guo, Sanyou Guo, Jianzhen Zhang, Shi-Hong Gu, Subba Reddy Palli, Yang Cao, Sheng Li

Entomology Faculty Publications

The temporal control mechanisms that precisely control animal development remain largely elusive. The timing of major developmental transitions in insects, including molting and metamorphosis, is coordinated by the steroid hormone 20-hydroxyecdysone (20E). 20E involves feedback loops to maintain pulses of ecdysteroid biosynthesis leading to its upsurge, whereas the underpinning molecular mechanisms are not well understood. Using the silkworm Bombyx mori as a model, we demonstrated that E75, the 20E primary response gene, mediates a regulatory loop between ecdysteroid biosynthesis and 20E signaling. E75 isoforms A and C directly bind to retinoic acid receptor-related response elements in Halloween gene promoter …

Go to article

The Hiv-1 Tat Protein Is Monomethylated At Lysine 71 By The Lysine Methyltransferase Kmt7, Ibraheem Ali, Holly Ramage, Daniela Boehm, Lynnette M. A. Dirk, Naoki Sakane, Kazuki Hanada, Sara Pagans, Katrin Kaehlcke, Katherine Aull, Leor Weinberger, Raymond Trievel, Martina Schnoelzer, Masafumi Kamada, Robert L. Houtz, Melanie Ott May 2016

The Hiv-1 Tat Protein Is Monomethylated At Lysine 71 By The Lysine Methyltransferase Kmt7, Ibraheem Ali, Holly Ramage, Daniela Boehm, Lynnette M. A. Dirk, Naoki Sakane, Kazuki Hanada, Sara Pagans, Katrin Kaehlcke, Katherine Aull, Leor Weinberger, Raymond Trievel, Martina Schnoelzer, Masafumi Kamada, Robert L. Houtz, Melanie Ott

Horticulture Faculty Publications

The HIV-1 transactivator protein Tat is a critical regulator of HIV transcription primarily enabling efficient elongation of viral transcripts. Its interactions with RNA and various host factors are regulated by ordered, transient post-translational modifications. Here, we report a novel Tat modification, monomethylation at lysine 71 (K71). We found that Lys-71 monomethylation (K71me) is catalyzed by KMT7, a methyltransferase that also targets lysine 51 (K51) in Tat. Using mass spectrometry, in vitro enzymology, and modification-specific antibodies, we found that KMT7 monomethylates both Lys-71 and Lys-51 in Tat. K71me is important for full Tat transactivation, as KMT7 knockdown impaired the transcriptional activity …

Go to article

Ubr3, A Novel Modulator Of Hh Signaling Affects The Degradation Of Costal-2 And Kif7 Through Poly-Ubiquitination, Tongchao Li, Junkai Fan, Bernardo Blanco-Sánchez, Nikolaos Giagtzoglou, Guang Lin, Shinya Yamamoto, Manish Jaiswal, Kuchuan Chen, Jie Zhang, Wei Wei, Michael T. Lewis, Andrew K. Groves, Monte Westerfield, Jianhang Jia, Hugo J. Bellen May 2016

Ubr3, A Novel Modulator Of Hh Signaling Affects The Degradation Of Costal-2 And Kif7 Through Poly-Ubiquitination, Tongchao Li, Junkai Fan, Bernardo Blanco-Sánchez, Nikolaos Giagtzoglou, Guang Lin, Shinya Yamamoto, Manish Jaiswal, Kuchuan Chen, Jie Zhang, Wei Wei, Michael T. Lewis, Andrew K. Groves, Monte Westerfield, Jianhang Jia, Hugo J. Bellen

Markey Cancer Center Faculty Publications

Hedgehog (Hh) signaling regulates multiple aspects of metazoan development and tissue homeostasis, and is constitutively active in numerous cancers. We identified Ubr3, an E3 ubiquitin ligase, as a novel, positive regulator of Hh signaling in Drosophila and vertebrates. Hh signaling regulates the Ubr3-mediated poly-ubiquitination and degradation of Cos2, a central component of Hh signaling. In developing Drosophila eye discs, loss of ubr3 leads to a delayed differentiation of photoreceptors and a reduction in Hh signaling. In zebrafish, loss of Ubr3 causes a decrease in Shh signaling in the developing eyes, somites, and sensory neurons. However, not all tissues that require …

Go to article

The Function Of Shoc2: A Scaffold And Beyond, Eun Ryoung Jang, Emilia Galperin May 2016

The Function Of Shoc2: A Scaffold And Beyond, Eun Ryoung Jang, Emilia Galperin

Molecular and Cellular Biochemistry Faculty Publications

The extracellular signal-regulated kinase (ERK1/2) cascade regulates a myriad of functions in multicellular organisms. Scaffold proteins provide critical spatial and temporal control over the specificity of signaling. Shoc2 is a scaffold that accelerates activity of the ERK1/2 pathway. Loss of Shoc2 expression in mice results in embryonic lethality, thus highlighting the essential role of Shoc2 in embryogenesis. In agreement, patients carrying mutated Shoc2 suffer from a wide spectrum of developmental deficiencies. Efforts to understand the mechanisms by which Shoc2 controls ERK1/2 activity revealed the intricate machinery that governs the ability of Shoc2 to transduce signals of the ERK1/2 pathway. Understanding …

Go to article

Quantitative Mass Spectrometry Reveals Changes In Histone H2b Variants As Cells Undergo Inorganic Arsenic-Mediated Cellular Transformation, Matthew Rea, Tingting Jiang, Rebekah Eleazer, Meredith Eckstein, Alan G. Marshall, Yvonne N. Fondufe-Mittendorf May 2016

Quantitative Mass Spectrometry Reveals Changes In Histone H2b Variants As Cells Undergo Inorganic Arsenic-Mediated Cellular Transformation, Matthew Rea, Tingting Jiang, Rebekah Eleazer, Meredith Eckstein, Alan G. Marshall, Yvonne N. Fondufe-Mittendorf

Molecular and Cellular Biochemistry Faculty Publications

Exposure to inorganic arsenic, a ubiquitous environmental toxic metalloid, leads to carcinogenesis. However, the mechanism is unknown. Several studies have shown that inorganic arsenic exposure alters specific gene expression patterns, possibly through alterations in chromatin structure. While most studies on understanding the mechanism of chromatin-mediated gene regulation have focused on histone post-translational modifications, the role of histone variants remains largely unknown. Incorporation of histone variants alters the functional properties of chromatin. To understand the global dynamics of chromatin structure and function in arsenic-mediated carcinogenesis, analysis of the histone variants incorporated into the nucleosome and their covalent modifications is required. Here …

Go to article

Single-Cell Transcriptional Analysis Of Normal, Aberrant, And Malignant Hematopoiesis In Zebrafish, Finola E. Moore, Elaine G. Garcia, Riadh Lobbardi, Esha Jain, Qin Tang, John C. Moore, Mauricio Cortes, Aleksey Molodtsov, Melissa Kasheta, Christina C. Luo, Amaris J. Garcia, Ravi Mylvaganam, Jeffrey A. Yoder, Jessica S. Blackburn, Ruslan I. Sadreyev, Craig J. Ceol, Trista E. North, David M. Langenau May 2016

Single-Cell Transcriptional Analysis Of Normal, Aberrant, And Malignant Hematopoiesis In Zebrafish, Finola E. Moore, Elaine G. Garcia, Riadh Lobbardi, Esha Jain, Qin Tang, John C. Moore, Mauricio Cortes, Aleksey Molodtsov, Melissa Kasheta, Christina C. Luo, Amaris J. Garcia, Ravi Mylvaganam, Jeffrey A. Yoder, Jessica S. Blackburn, Ruslan I. Sadreyev, Craig J. Ceol, Trista E. North, David M. Langenau

Molecular and Cellular Biochemistry Faculty Publications

Hematopoiesis culminates in the production of functionally heterogeneous blood cell types. In zebrafish, the lack of cell surface antibodies has compelled researchers to use fluorescent transgenic reporter lines to label specific blood cell fractions. However, these approaches are limited by the availability of transgenic lines and fluorescent protein combinations that can be distinguished. Here, we have transcriptionally profiled single hematopoietic cells from zebrafish to define erythroid, myeloid, B, and T cell lineages. We also used our approach to identify hematopoietic stem and progenitor cells and a novel NK-lysin 4+ cell type, representing a putative cytotoxic T/NK cell. Our platform …

Go to article

Novel Interactome Of Saccharomyces Cerevisiae Myosin Type Ii Identified By A Modified Integrated Membrane Yeast Two-Hybrid (Imyth) Screen, Ednalise Santiago, Pearl Akamine, Jamie Snider, Victoria Wong, Matthew Jessulat, Viktor Deineko, Alla Gagarinova, Hiroyuki Aoki, Zoran Minic, Sadhna Phanse, Andrea San Antonio, Luis A Cubano, Brian C. Rymond, Mohan Babu, Igor Stagljar, Jose R. Rodriguez-Medina May 2016

Novel Interactome Of Saccharomyces Cerevisiae Myosin Type Ii Identified By A Modified Integrated Membrane Yeast Two-Hybrid (Imyth) Screen, Ednalise Santiago, Pearl Akamine, Jamie Snider, Victoria Wong, Matthew Jessulat, Viktor Deineko, Alla Gagarinova, Hiroyuki Aoki, Zoran Minic, Sadhna Phanse, Andrea San Antonio, Luis A Cubano, Brian C. Rymond, Mohan Babu, Igor Stagljar, Jose R. Rodriguez-Medina

Biology Faculty Publications

Nonmuscle myosin type II (Myo1p) is required for cytokinesis in the budding yeast Saccharomyces cerevisiae. Loss of Myo1p activity has been associated with growth abnormalities and enhanced sensitivity to osmotic stress, making it an appealing antifungal therapeutic target. The Myo1p tail-only domain was previously reported to have functional activity equivalent to the full-length Myo1p whereas the head-only domain did not. Since Myo1p tail-only constructs are biologically active, the tail domain must have additional functions beyond its previously described role in myosin dimerization or trimerization. The identification of new Myo1p-interacting proteins may shed light on the other …

Go to article

Twist-Mediated Epithelial-Mesenchymal Transition Promotes Breast Tumor Cell Invasion Via Inhibition Of Hippo Pathway, Yifan Wang, Jingyi Liu, Xuhua Ying, Pengnian Charles Lin, Binhua P. Zhou Apr 2016

Twist-Mediated Epithelial-Mesenchymal Transition Promotes Breast Tumor Cell Invasion Via Inhibition Of Hippo Pathway, Yifan Wang, Jingyi Liu, Xuhua Ying, Pengnian Charles Lin, Binhua P. Zhou

Molecular and Cellular Biochemistry Faculty Publications

Twist is a key transcription factor for Epithelial-mesenchymal transition (EMT), which is a cellular de-differentiation program that promotes invasion and metastasis, confers tumor cells with cancer stem cell (CSC)-like characteristics, and increases therapeutic resistance. However, the mechanisms that facilitate the functions of Twist remain unclear. Here we report that Twist overexpression increased expression of PAR1, an upstream regulator of the Hippo pathway; PAR1 promotes invasion, migration, and CSC-like properties in breast cancer by activating the transcriptional co-activator TAZ. Our study indicates that Hippo pathway inhibition is required for the increased migratory and invasiveness ability of breast cancer cells in Twist-mediated …

Go to article

Steroid Binding To Autotaxin Links Bile Salts And Lysophosphatidic Acid Signalling, Willem-Jan Keune, Jens Hausmann, Ruth Bolier, Dagmar Tolenaars, Andreas Kremer, Tatjana Heidebrecht, Robbie P. Joosten, Manjula Sunkara, Andrew J. Morris, Elisa Matas-Rico, Wouter H. Moolenaar, Ronald P. Oude Elferink, Anastassis Perrakis Apr 2016

Steroid Binding To Autotaxin Links Bile Salts And Lysophosphatidic Acid Signalling, Willem-Jan Keune, Jens Hausmann, Ruth Bolier, Dagmar Tolenaars, Andreas Kremer, Tatjana Heidebrecht, Robbie P. Joosten, Manjula Sunkara, Andrew J. Morris, Elisa Matas-Rico, Wouter H. Moolenaar, Ronald P. Oude Elferink, Anastassis Perrakis

Gill Heart & Vascular Institute Faculty Publications

Autotaxin (ATX) generates the lipid mediator lysophosphatidic acid (LPA). ATX-LPA signalling is involved in multiple biological and pathophysiological processes, including vasculogenesis, fibrosis, cholestatic pruritus and tumour progression. ATX has a tripartite active site, combining a hydrophilic groove, a hydrophobic lipid-binding pocket and a tunnel of unclear function. We present crystal structures of rat ATX bound to 7α-hydroxycholesterol and the bile salt tauroursodeoxycholate (TUDCA), showing how the tunnel selectively binds steroids. A structure of ATX simultaneously harbouring TUDCA in the tunnel and LPA in the pocket, together with kinetic analysis, reveals that bile salts act as partial non-competitive inhibitors …

Go to article

Photocatalytic Reduction Of Fumarate To Succinate On Zns Mineral Surfaces, Ruixin Zhou, Marcelo I. Guzman Apr 2016

Photocatalytic Reduction Of Fumarate To Succinate On Zns Mineral Surfaces, Ruixin Zhou, Marcelo I. Guzman

Chemistry Faculty Publications

The reductive tricarboxylic acid (rTCA) cycle is an important central biosynthetic pathway that fixes CO2 into carboxylic acids. Among the five reductive steps in the rTCA cycle, the two-electron reduction of fumarate to succinate proceeds nonenzymatically on the surface of photoexcited sphalerite (ZnS) colloids suspended in water. This model reaction is chosen to systematically study the surface photoprocess occurring on ZnS in the presence of [Na2S] (1–10 mM) hole scavenger at 15 °C. Experiments at variable pH (5–10) indicate that monodissociated fumaric acid is the primary electron acceptor forming the monoprotic form of succinic acid. The following …

Go to article

Tumor Suppressor Spred2 Interaction With Lc3 Promotes Autophagosome Maturation And Induces Autophagy-Dependent Cell Death, Ke Jiang, Min Liu, Guibin Lin, Beibei Mao, Wei Cheng, Han Liu, Jozsef Gal, Haining Zhu, Zengqiang Yuan, Wuguo Deng, Quentin Liu, Peng Gong, Xiaolin Bi, Songshu Meng Mar 2016

Tumor Suppressor Spred2 Interaction With Lc3 Promotes Autophagosome Maturation And Induces Autophagy-Dependent Cell Death, Ke Jiang, Min Liu, Guibin Lin, Beibei Mao, Wei Cheng, Han Liu, Jozsef Gal, Haining Zhu, Zengqiang Yuan, Wuguo Deng, Quentin Liu, Peng Gong, Xiaolin Bi, Songshu Meng

Molecular and Cellular Biochemistry Faculty Publications

The tumor suppressor Spred2 (Sprouty-related EVH1 domain-2) induces cell death in a variety of cancers. However, the underlying mechanism remains to be elucidated. Here we show that Spred2 induces caspase-independent but autophagy-dependent cell death in human cervical carcinoma HeLa and lung cancer A549 cells. We demonstrate that ectopic Spred2 increased both the conversion of microtubule-associated protein 1 light chain 3 (LC3), GFP-LC3 puncta formation and p62/SQSTM1 degradation in A549 and HeLa cells. Conversely, knockdown of Spred2 in tumor cells inhibited upregulation of autophagosome maturation induced by the autophagy inducer Rapamycin, which could be reversed by the rescue Spred2. These data …

Go to article

Arf6 Controls Platelet Spreading And Clot Retraction Via Integrin ΑIibΒ3 Trafficking, Yunjie Huang, Smita Joshi, Binggang Xiang, Yasunori Kanaho, Zhenyu Li, Beth A. Bouchard, Carole L. Moncman, Sidney W. Whiteheart Mar 2016

Arf6 Controls Platelet Spreading And Clot Retraction Via Integrin ΑIibΒ3 Trafficking, Yunjie Huang, Smita Joshi, Binggang Xiang, Yasunori Kanaho, Zhenyu Li, Beth A. Bouchard, Carole L. Moncman, Sidney W. Whiteheart

Molecular and Cellular Biochemistry Faculty Publications

Platelet and megakaryocyte endocytosis is important for loading certain granule cargo (ie, fibrinogen [Fg] and vascular endothelial growth factor); however, the mechanisms of platelet endocytosis and its functional acute effects are understudied. Adenosine 5'-diphosphate–ribosylation factor 6 (Arf6) is a small guanosine triphosphate–binding protein that regulates endocytic trafficking, especially of integrins. To study platelet endocytosis, we generated platelet-specific Arf6 knockout (KO) mice. Arf6 KO platelets had less associated Fg suggesting that Arf6 affects αIIbβ3-mediated Fg uptake and/or storage. Other cargo was unaffected. To measure Fg uptake, mice were injected with biotinylated- or fluorescein isothiocyanate (FITC)–labeled Fg. Platelets …

Go to article

Ubiquitin-Specific Peptidase 10 (Usp10) Deubiquitinates And Stabilizes Muts Homolog 2 (Msh2) To Regulate Cellular Sensitivity To Dna Damage, Mu Zhang, Chen Hu, Dan Tong, Shengyan Xiang, Kendra Williams, Wenlong Bai, Guo-Min Li, Gerold Bepler, Xiaohong Zhang Mar 2016

Ubiquitin-Specific Peptidase 10 (Usp10) Deubiquitinates And Stabilizes Muts Homolog 2 (Msh2) To Regulate Cellular Sensitivity To Dna Damage, Mu Zhang, Chen Hu, Dan Tong, Shengyan Xiang, Kendra Williams, Wenlong Bai, Guo-Min Li, Gerold Bepler, Xiaohong Zhang

Toxicology and Cancer Biology Faculty Publications

MSH2 is a key DNA mismatch repair protein, which plays an important role in genomic stability. In addition to its DNA repair function, MSH2 serves as a sensor for DNA base analogs-provoked DNA replication errors and binds to various DNA damage-induced adducts to trigger cell cycle arrest or apoptosis. Loss or depletion of MSH2 from cells renders resistance to certain DNA-damaging agents. Therefore, the level of MSH2 determines DNA damage response. Previous studies showed that the level of MSH2 protein is modulated by the ubiquitin-proteasome pathway, and histone deacetylase 6 (HDAC6) serves as an ubiquitin E3 ligase. However, the deubiquitinating …

Go to article

Next Last